/Engine/Plugins/Experimental/RenderGrid/Source/RenderGrid/Public/RenderGrid/RenderGrid.h
It's currently simply a wrapper around a byte array. This struct is needed so that that byte array can be used in another UPROPERTY container (TMap,TArray, etc).
[USTRUCT](Programming/UnrealArchitecture/Reference/Structs)([BlueprintType](Programming/UnrealArchitecture/Reference/Structs/Specifiers/BlueprintType)) struct FRenderGridRemoteControlPropertyData
TArray< uint8 >
Bytes
The property data, as bytes.